You mean the thing that our intel agencies, Senate Intel committee all agreed that Russia interfered in the election to help Trump, and that we have numerous DOCUMENTED cases where Trump campaign people met with Russians, his campaign chief shared polling data, etc?
I'll agree that Hillary shouldn't have called him an illegitimate president...but 1) she DID concede the election; and 2) quite honestly, I view everything she's said since about the election thru the lens of a woman who still can't believe she lost to that guy.